Poster #57 - Development of motor planning: Object placement in children at elevated vs. typical likelihood for autism

• In Event: Poster Session 20

Abstract

When performing object placement tasks, toddlers, like adults, exhibit motor planning. Their movements are faster when reaching for and placing objects in an imprecise condition (e.g., throwing blocks into a bin) vs. a precise condition (e.g., building a tower). Toddlers with an elevated likelihood (EL) of autism spectrum disorder (ASD) display early delays in fine motor skills compared to peers with typical ASD likelihood (TL). Previous research with EL toddlers at 24 and 36 months found evidence of motor planning, i.e., slower movements in precise compared to imprecise conditions. Here we examined performance in an object placement task at four timepoints, beginning at 12 months, to track the emergence and development of motor planning across the second and third years.

We observed 42 children (19 EL, 23 TL) at 12, 18, 24, and 36 months performing a motor task that included two conditions varying in the degree of precision required to place a ball into an aperture. In the imprecise task, children threw a ball into a large open tub, and in the precise task children inserted the ball into a clear plastic tube. From video, coders identified duration of object placement, beginning when the ball was lifted from the table and ending when the ball was aligned with the target (i.e., tub or tube). Children also wore magneto-inertial sensors on both wrists to collect kinematic data during each trial used to calculate mean acceleration (in cm/s2).

Data were analyzed using Hierarchical Linear Models (HLM). There were no differences based on ASD likelihood, so groups were collapsed. In both conditions, we observed a significant quadratic decrease in placement duration (or the time it took children to place the ball) across the four sessions (ps < .05). Specifically, there was a steep decrease between 12 and 18 months and then a flattening in change across the rest of the observation period. Analyses also indicated that toddlers became faster at placing the ball (i.e., displayed greater accelerations) as they got older, and this growth was linear (ps < .05). Finally, we observed an effect of task difficulty. At all ages, toddlers took significantly more time to place the ball in the tube (precise condition) than in the tub (imprecise condition). However, the effect of precision was only apparent for accelerations at 24 and 36 months (when toddlers had significantly lower accelerations in the precise condition), suggesting that there was developmental change in children’s sensitivity to task demands, with the difference between conditions becoming pronounced by 24 months (ps < .05; Figure 1).

Taken together, findings suggest that toddlers generally were slower and took longer to place objects when there were greater demands for the goal action (precise condition). Moreover, EL toddlers demonstrated similar placement skills to their TL peers, suggesting that early differences in fine motor skills may not affect later motor planning abilities. Future work will continue assessing motor planning in EL and TL toddlers using more complex motor tasks (e.g., shape sorter tasks).

Authors

• Kaitlyn B Cortez, University of Pittsburgh

• Madyson R Diehl, University of Pittsburgh
  Presenting Author

• Hayden Timmins

• Joshua L Schneider, University of Pittsburgh

• Valentina Focaroli, Universita' Campus-Biomedico

• Fabrizio Taffoni, Università Campus Bio-Medico

• Flavio Keller, Universita' Campus-Biomedico

• Jana M Iverson, Boston University